Decorating leather



Feb. 2 i932. A. SCHUBERT l 1,843,738

' DECORATING LEATHER Filed July 6, 1929 INVENToR.

" BY 7 @Mw Wm K n ATTO EYS.

Patented Feb. 2, 1932 UNITED STATES PATENT OFFICE .ADOLF SCHUBERT, 0FMILLBURN, NEW JERSEY, ASSIGNOR TO BARRETT & COMPANY,

0F NEWARK, NEW JERSEY, A CORPORATION 0F NEW JERSEY DECORATING- LEATHERApplication ined July 6, 1929. serial No. 376,494.

My invention is a process resembling those transfer-printing processesin which the subject matter is printed initially on sheets of paper, andfrom these sheets is transferred, by contact and pressure in thepresence of a suitable fluid, to the articles or materials to receivethe print. So far as I am aware however none of the priortransfer-printing processes are suitable for the decoration of leather:the reasons are various, among these being the non-suitability of thesubstances used, and the tendency of the colors to bleed whereby linesare blurred and color gradations tend to disappear. The object of myinvention is to provide a process of the transfer-printing` type whichis suitable for decorating leather.

- The accompanying drawing illustrates, diagrammatically` an embodimentof my 1n vention.

According to my invention, the colormg matter used in the ink is a dyeor mixture of dyes rather than a pigment (including color lakes withinthe term pigment) that is to say the coloring matter used in the ink isa soluble substance capable of directly affixing itself to and dyeingthe fibres of the leather from solution. Furthermore, the coloringmatter used is one (or a mixture) of those dyes which are soluble inalcohol and insoluble in water. This class of dyes covers a wide rangeof fast colors and a Wide range of dyes which are insoluble or. onlyvery slightly soluble in those "materials or substances which aresuitable for the vehicles with which the dyes are mixed to form theprinting ink as hereinafter described.

For the vehicle part of the ink, that is to say, for the carrier for thedyestufl' and which serves to give the ink the necessary viscosity,greasy or tacky nature, and any other characteristics that may berequired of inksr employed in the particular printing process chosen forlaying down the subject matter on the transfer sheetsfI choose asubstance or substances that will remain on the transfer sheets for someconsiderable. time, that is or are soluble in the transfer-solvent usedin making the transfer to the leather, and a sub.

alcohol-soluble resin or gum, for example f/ lution.

stance or substances in which the dye or dyes 1s substantiallyinsoluble. Various of the fixed or non-drying oils and fats meet theserequirements, and particularly the vegetable and animal oils and fats ofthe non-drying class. Preferably I use castor oil. Such substances canbe thickened to the required consistency by suitable substances such asan rosin, shellac, elimi, mastic, sandarac, etc. Such thickeners Iusually mix with the oil or fat before introducing the dye. The dye ordyes is intermixed with the vehicle of course. At the time the printingis done on the transfer sheets, the dyestul should be in a solid state,rather than in so- Preferably therefore I grindthe dry, finely powdereddye, or mixture of dyes into the vehicle. I use such proportions as testshows to give the proper strength' of 7d color or tinctorial value onthe \leather. If necessary the mixture can be thinned somewhatthereafter by adding a more fluid substance inert to the dye butmiscible to the vehicle, such as xylol, toluol, benzolfetc; theseparticular thinners do not seem to materially reduce the color strengthor tinctorial value,

L lpresumably because of their volatility. The

dye-vehicle mixture can also be thickened somewhat by adding more oil orfat and resin or gum in suitable proportions, but this tends to reducethe color strength as will be apparent. i

With such anA ink, the subject matter is printed onto the transfersheets, for example by blocks or rolls engraved 'or etched in accordancewith the design or ornamentation. Forv the transfer sheets I preferablyuse a fibrous material, such as paper or cloth, because of itspermeability to the transfer-solvent. A substantially unsized anduncalendered paper, such as is used for newspapers, servesthe purposewell.

not attack the leather, and which preferably Alo has a high degree-ofcapillarity. Suitable for this transfer-solvent, so-called, arel theorganic acidsvsuch as oxalic, acetic and taris satisfactory. I believethat the waterinsoluble characteristic of the dye is beneficial inl thedirection of rendering the presence of some water in thetransfer-solvent permissible; specifically it renders absolute alcoholunnecessary. In making the transfer, I apply the 'transfer-solvent tothe leather, and apply the transfer sheet dry to the wetted leather. Theleather can be dipped/in the transfer-solvent, or the tr-ansfer solventsprayed on to the leather, for example. To the wetted leather the inkface of the transfer sheet is then applied and the two are Ipressed intouniform and close contact. For this purpose I preferably squeeze the twoin a press, and I have used up to threehundred pounds per square inchpressure. It is not to` be understood however that pressures of thisorder are necessary, but pressure of this order serve to bring thetransfer sheet and leather into uniformly close contact throughout thewhole area despite the fact that the thickness of the leather may varyconsiderably from point to. point. After the two have been pressedtogether momentarily, the pressure is released and the transfer sheetpeeled od the leather, whereupon lit will be found that the leather hasbeen dyed in accordance with the subject matter as initially printed onthe transfer sheet and with the same degree of clarity of outline andgradation of color, and with an adequate strength of color or tinctorialvalue. If desired, heat can be applied at the saine time'as thepressure, as by steam-heating the plates of the press. The use of heatis not an essential ordinarily however. After the transfer sheet isremoved, the transfer-solvent can be removed from the leather byevaporation; in fact if grain alcohol is used as the transfer-solvent,this will disappear quicklly by natural evaporation.

It willy be understood that my invention is not limited to the detailsdescribed above except as appears hereinafter in the claims.

I claim: y

1. The inethod of decorating leather which consists in-printing thesubject matter on sheets of fibrous material with an ink comprising adye in a form capable of directly 'dyeing the libres of the leather fromsolution and which is insoluble in 'water and soluble 1n alcohol, and avehicle suiting the ink to Lsaavss 'or fat, which is substantially not asolvent forthe dye, and which is soluble in the solvent hereinaftermentioned, the dye and vehicle being mixed together and the dye being ina solid state, pressing, while the saidoil or fat is still on thesheets, one of said sheets into smooth contact with a leather inthepresence of a solvent for the dye and a solventfor the vehicle, and thenremoving the sheet from the leather. l A

2. The method of decorating leather which consists in mixing a dye in aform capable of directly dyeing the fibres of the leather from solutionand which is insoluble in water but is soluble in alcohol, the dye beingin a finely powdered solid state, with a non-drying oil or fat which issoluble in the solvent hereinafter mentioned and which is substantiallynot a solvent forthe dye, and which suits, with or without the additionofanother f solvent-soluble or inert substance thejv resultl ing ink tothe particular printing process by which the sheets hereinaftermentioned are printed, printing the subject matter on sheets of fibrousmaterial with said ink, applying, while the said oil or fat is still onthe sheets, one of said sheets to a leather, inked face to the leather,in the presence of a solvent for the dye and a solvent for the said oilor fat, pressing the sheet into firm smooth contact with the leather,and then removing the sheet dye and consisting of a substantially non!drying vegetable or animal oil or fat and an alcohol-soluble resin orgum, the dye and vehicle being mixed together and the dye being in asolid state, pressing, while the vehicle is still present on the sheets,one of said sheets to a leather in the presence of a. transfer-solventof the class of t ose hereinbefore specifically named, the ed face ofthe sheet being applied to the leather, and then removing the sheetfrom'the leather.

4. The method of decorating leather which consists in printing thesubject matter on sheets of a fibrous material with an ink coniprising adye in a form capable of directly dyeing the leather from solution andwhich is insoluble in water but soluble in alcohol, and

a vehicle not a solvent for theldye and consistapplyin to a' leather a.solvent for the dye and a so vent for said vehicle, pressing one of saidsheets to said leather while the solvent is still in the leatherandvehicle is still on the sheet, and then removing the sheet from theleather.

5. The subject matter of claim 1, characterized by the fact that thebrous material is a substantially unsized and uncalendered pa er.

n testimony whereof, I have signed this specification. v v ADOLFSCHUBERT.

